Re: [linux-next:master 5868/6773] arch/powerpc/mm/mem.c:91:12: warning: no previous prototype for function 'create_section_mapping'

[Dan Williams <dan.j.williams@intel.com>]

On Wed, Nov 18, 2020 at 4:27 AM kernel test robot <lkp@intel.com> wrote:
>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   2052923327794192c5d884623b5ee5fec1867bda
> commit: d106ad47e292fde47fc09e16a2ddc13609ff2ad1 [5868/6773] mm-fix-phys_to_target_node-and-memory_add_physaddr_to_nid-exports-v4
> config: powerpc64-randconfig-r026-20201118 (attached as .config)
> compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project b2613fb2f0f53691dd0211895afbb9413457fca7)
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # install powerpc64 cross compiling tool for clang build
>         # apt-get install binutils-powerpc64-linux-gnu
>         # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=d106ad47e292fde47fc09e16a2ddc13609ff2ad1
>         git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
>         git fetch --no-tags linux-next master
>         git checkout d106ad47e292fde47fc09e16a2ddc13609ff2ad1
>         # save the attached .config to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc64

I get:

Makefile:597: arch/powerpc64/Makefile: No such file or directory
make[1]: *** No rule to make target 'arch/powerpc64/Makefile'.  Stop.
make: *** [Makefile:712: include/config/auto.conf.cmd] Error 2

...changing it to ARCH=powerpc I get:

Assembler messages:
Fatal error: invalid listing option `3'
clang: error: assembler command failed with exit code 1 (use -v to see
invocation)
make[1]: *** [scripts/Makefile.build:283: scripts/mod/empty.o] Error 1
make[1]: *** Waiting for unfinished jobs....
make: *** [Makefile:1199: prepare0] Error 2

This is on a Fedora 31 host.

>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> All warnings (new ones prefixed by >>):
>
> >> arch/powerpc/mm/mem.c:91:12: warning: no previous prototype for function 'create_section_mapping' [-Wmissing-prototypes]
>    int __weak create_section_mapping(unsigned long start, unsigned long end,
>               ^
>    arch/powerpc/mm/mem.c:91:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
>    int __weak create_section_mapping(unsigned long start, unsigned long end,
>    ^
>    static
>    1 warning generated.

I do not see these errors with gcc.

I feel like clang errors should be flagged / de-emphasized when the
same error does not appear on gcc.